I will buy kessil when the price levels off, hopfully well under $200.
In the meantime I have experimented with generic chinese and blackstar LED panels. While I have great interest in the technology and efficiency purported by kessil I intuitively have to believe the better panels still give more bang for the buck, particularly with grows over a square meter in size. Other than that statement anything I surmise about kessil is just hypothetical until I run the them. What i will say is that the better panels of 200 W and above can produce superior buds, produce very little heat and are a viable alternative to HID for me.
The kessil advantage as outlined by their web presentations are seductive but slightly flawed. Regardless of the efficient use of electricity,specific spectra and optics the Kessils do not generate a huge vollume of photons.
On top of that the lens that allows penetration may cause burning if placed closer than 12 to 18" from the canopy. I look forward to the evolution of our light sources.